Add command line switch to output warnings to stderr - close #26

lib/propane.rb

@@ -31,10 +31,10 @@ class Propane
 
   class << self
 
-    def run(input_file, output_file, log_file)
+    def run(input_file, output_file, log_file, options)
       begin
         grammar = Grammar.new(File.read(input_file))
-        generator = Generator.new(grammar, output_file, log_file)
+        generator = Generator.new(grammar, output_file, log_file, options)
         generator.generate
       rescue Error => e
         $stderr.puts e.message

lib/propane/cli.rb

@@ -4,15 +4,21 @@ class Propane
     USAGE = <<EOF
 Usage: #{$0} [options] <input-file> <output-file>
 Options:
-  --log LOG   Write log file
-  --version   Show program version and exit
-  -h, --help  Show this usage and exit
+  --log LOG   Write log file. This will show all parser states and their
+              associated shifts and reduces. It can be helpful when
+              debugging a grammar.
+  --version   Show program version and exit.
+  -h, --help  Show this usage and exit.
+  -w          Treat warnings as errors. This option will treat shift/reduce
+              conflicts as fatal errors and will print them to stderr in
+              addition to the log file.
 EOF
 
     class << self
 
       def run(args)
         params = []
+        options = {}
         log_file = nil
         i = 0
         while i < args.size
@@ -29,6 +35,8 @@ EOF
           when "-h", "--help"
             puts USAGE
             return 0
+          when "-w"
+            options[:warnings_as_errors] = true
           when /^-/
             $stderr.puts "Error: unknown option #{arg}"
             return 1
@@ -45,7 +53,7 @@ EOF
           $stderr.puts "Error: cannot read #{params[0]}"
           return 2
         end
-        Propane.run(*params, log_file)
+        Propane.run(*params, log_file, options)
       end
 
     end

lib/propane/generator.rb

@@ -2,7 +2,7 @@ class Propane
 
   class Generator
 
-    def initialize(grammar, output_file, log_file)
+    def initialize(grammar, output_file, log_file, options)
       @grammar = grammar
       @output_file = output_file
       if log_file
@@ -16,6 +16,7 @@ class Propane
         else
           "d"
         end
+      @options = options
       process_grammar!
     end
 
@@ -129,7 +130,7 @@ class Propane
       # Generate the lexer.
       @lexer = Lexer.new(@grammar)
       # Generate the parser.
-      @parser = Parser.new(@grammar, rule_sets, @log)
+      @parser = Parser.new(@grammar, rule_sets, @log, @options)
     end
 
     # Check that any referenced ptypes have been defined.

lib/propane/parser.rb

@@ -7,13 +7,14 @@ class Propane
     attr_reader :reduce_table
     attr_reader :rule_sets
 
-    def initialize(grammar, rule_sets, log)
+    def initialize(grammar, rule_sets, log, options)
       @grammar = grammar
       @rule_sets = rule_sets
       @log = log
       @item_sets = []
       @item_sets_set = {}
-      @sr_conflicts = Set.new
+      @warnings = Set.new
+      @options = options
       start_item = Item.new(grammar.rules.first, 0)
       eval_item_sets = Set[ItemSet.new([start_item])]
 
@@ -41,6 +42,9 @@ class Propane
       build_follow_sets!
       build_tables!
       write_log!
+      if @warnings.size > 0 && @options[:warnings_as_errors]
+        raise Error.new("Fatal errors (-w):\n" + @warnings.join("\n"))
+      end
     end
 
     private
@@ -65,7 +69,7 @@ class Propane
         if item_set.reduce_actions
           shift_entries.each do |shift_entry|
             if item_set.reduce_actions.include?(shift_entry[:symbol])
-              @sr_conflicts << [shift_entry[:symbol], item_set.reduce_actions[shift_entry[:symbol]]]
+              @warnings << "Shift/Reduce conflict between token #{shift_entry[:symbol].name} and rule #{item_set.reduce_actions[shift_entry[:symbol]].name}"
             end
           end
         end
@@ -318,11 +322,11 @@ class Propane
           end
         end
       end
-      if @sr_conflicts.size > 0
+      if @warnings.size > 0
         @log.puts
-        @log.puts "Shift/Reduce Conflicts:"
-        @sr_conflicts.each do |sr_conflict|
-          @log.puts "  Shift/Reduce conflict between #{sr_conflict[0].name} and #{sr_conflict[1].name}"
+        @log.puts "Warnings:"
+        @warnings.each do |warning|
+          @log.puts "  #{warning}"
         end
       end
     end

spec/propane_spec.rb

@@ -54,6 +54,7 @@ EOF
     else
       command += %W[spec/run/testparser#{options[:name]}.propane spec/run/testparser#{options[:name]}.#{options[:language]} --log spec/run/testparser#{options[:name]}.log]
     end
+    command += (options[:extra_args] || [])
     if (options[:capture])
       stdout, stderr, status = Open3.capture3(*command)
       Results.new(stdout, stderr, status)
@@ -195,7 +196,21 @@ EOF
     results = run_propane(capture: true)
     expect(results.stderr).to eq ""
     expect(results.status).to eq 0
-    expect(File.binread("spec/run/testparser.log")).to match %r{Shift/Reduce conflict between b and As2}
+    expect(File.binread("spec/run/testparser.log")).to match %r{Shift/Reduce conflict between token b and rule As2}
+  end
+
+  it "errors on shift/reduce conflicts with -w" do
+    write_grammar <<EOF
+token a;
+token b;
+Start -> As? b?;
+As -> a As2?;
+As2 -> b a As2?;
+EOF
+    results = run_propane(extra_args: %w[-w], capture: true)
+    expect(results.stderr).to match %r{Fatal errors \(-w\).*Shift/Reduce conflict between token b and rule As2}m
+    expect(results.status).to_not eq 0
+    expect(File.binread("spec/run/testparser.log")).to match %r{Shift/Reduce conflict between token b and rule As2}
   end
 
   %w[d c].each do |language|